WO2020083390A1 - Method, device and system for acquiring blood flow of large artery on heart surface, and storage medium - Google Patents

Abstract

A method for accurately acquiring the blood flow of a certain large artery on the heart surface on the basis of a CT image, comprising: according to the volume of the myocardium, acquiring a first blood flow Q_t at the inlet of the coronary vessel in a maximum hyperemia (S200); according to the first blood flow Q_t, acquiring a second blood flow Q of any one of the aortic blood vessels and downstream blood vessels on the heart surface (S300); and performing Fourier transformation on the second blood flow Q in sequence, so as to obtain Q_f in the frequency domain (S400). Said method improves the accuracy of assessment parameter measurement for the coronary arterial blood vessels. Further disclosed are a corresponding device and system, and a storage medium.

Description

Method, device, system and storage medium for obtaining blood flow of cardiac surface aorta Technical field

The invention relates to the technical field of coronary arteries, in particular to a method, a device, a coronary artery analysis system and a computer storage medium for accurately acquiring blood flow of a large artery on the cardiac surface based on CT images.

Background technique

According to statistics from the World Health Organization, cardiovascular disease has become the "number one killer" of human health. In recent years, the use of hemodynamics to analyze the physiological and pathological behavior of cardiovascular diseases has also become a very important method for the diagnosis of cardiovascular diseases.

Blood flow and flow rate are very important parameters of hemodynamics. How to measure blood flow rate and flow rate accurately and conveniently has become the focus of research.

Coronary CTA can accurately assess the degree of coronary stenosis, and can distinguish the nature of tube wall plaque. It is a non-invasive and simple operation method for diagnosing coronary artery disease. It can be used as the first choice for screening high-risk groups. Therefore, if intervention is made on the blood vessels of patients with coronary heart disease, the blood vessel assessment parameters of the patients' coronary arteries should be measured in the early stage.

The vascular assessment parameters include: FFR, IMR, etc .; FFR and IMR need to be based on the average blood flow velocity of the coronary artery, and the average blood flow velocity is related to the blood flow of a large artery on the heart surface of the coronary artery, so any of the heart surface The measurement accuracy of the blood flow of the root aorta directly affects the measurement accuracy of the blood vessel evaluation parameters, and the blood flow measured by the method of the prior art has the problem of inaccuracy.

Summary of the invention

The invention provides a non-invasive detection method, a method, device, system and storage medium for obtaining blood flow of aorta on the surface of the heart according to a known flow velocity waveform to solve a large artery on the surface of the heart obtained by non-invasive surgery in the prior art and its The problem of inaccurate branch blood flow.

To achieve the above objective, in the first aspect, the present application provides a method for accurately acquiring blood flow of a large artery on the cardiac surface based on CT images, including:

Obtain maximum congestion based on myocardial volume and a known flow velocity waveform (in the maximum hyperemia state, the waveform in the left anterior descending branch, right coronary artery, and left circumflex branch of any patient measured by Doppler ultrasound guide wire) The waveform of the first blood flow Q _t at the entrance of coronary artery

Obtaining the second blood flow Q waveform of any aortic blood vessel on the surface of the heart and the downstream blood vessel according to the first blood flow Q _t waveform;

Perform a Fourier transform on the second blood flow Q waveform in sequence to obtain a corrected third blood flow Q _f waveform.

Optionally, the above method for accurately acquiring the blood flow of a large artery on the heart surface based on the CT image, before the method of acquiring the first blood flow Q _t at the entrance of the coronary artery in the state of maximum congestion according to the volume of the myocardium Including: three-dimensional reconstruction of myocardium based on cardiac CT images, specifically:

Segment the CT image of the heart to obtain CT image information of the computed tomography angiography of the heart;

Reconstruction to obtain a three-dimensional image of the heart;

Separately obtain a three-dimensional image of the myocardium from the three-dimensional image of the heart. Optionally, the above method for accurately acquiring the blood flow of a large artery on the cardiac surface based on the CT image, the method for acquiring the first blood flow Q _t at the entrance of the coronary artery according to the myocardial volume and a known flow velocity waveform includes :

Determine the myocardial volume V _r according to the three-dimensional image of the myocardium;

According to the volume of myocardium, the first blood flow Q _t at the entrance of the coronary artery under the maximum congestion state is obtained, the formula is:

Q _tmean = V _r × Q ₀ × K;

Among them, V _r represents myocardial volume; Q ₀ represents myocardial blood flow in resting state, Q _{0 is} obtained by cardiac MRI or CT perfusion, or Q ₀ = 2 ～ 2.8ml / min / g; K represents a constant;

Based on the Q _{t mean} and the CT image, the time t ₁ of the heartbeat cycle of the CT image is obtained;

Adjust the heartbeat cycle time on the known flow velocity waveform to t ₁ ;

According to the flow velocity multiplied by the cross-sectional area equal to the blood flow Q _a , obtain the Q _a -it ₁ flow waveform, where i represents the number of heartbeat cycles contained in the Q _a -it ₁ flow waveform, i≥1;

According to the formula:

Among them, Q _at means to obtain the average value of Q _a in j heartbeat cycles in the flow waveform of Q _a -it ₁ , 1≤j≤i;

According to the formula Q _t = Q _a × Q _{t mean} / Q _at , the first blood flow Q _t waveform is obtained.

Optionally, the above method for accurately acquiring blood flow of a large artery on the heart surface based on CT images. The method for acquiring the second blood flow Q of any aortic blood vessel on the surface of the heart and its downstream blood vessels includes:

Separate the three-dimensional image of the coronary artery tree from the three-dimensional image of the myocardium;

According to the three-dimensional image of the coronary artery tree, the volume sum V _{1 of} any aortic vessel on the surface of the heart and its downstream vessels is obtained;

Obtain the sum V _t of the volume of all blood vessels on the heart surface according to the three-dimensional image of the coronary artery tree;

Obtain the second blood flow Q according to Q _t , V ₁ , and V _t , the specific formula is:

Q = Q _t × (V ₁ / V _t ) ^3/4 .

Optionally, the above method for accurately acquiring blood flow of a large artery on the heart surface based on CT images, the method for separating and obtaining a three-dimensional image of the coronary artery tree from the three-dimensional image of the myocardium includes:

Extract the aorta image according to the three-dimensional image of the heart, process the aorta image to obtain a complete aorta complementary image, perform regional growth, and obtain an aorta image including a coronary artery entrance;

Determine the entrance of the coronary artery based on the image of the aorta containing the entrance of the coronary artery and the complementary image of the whole aorta to obtain an image containing the entrance of the coronary artery;

Taking the coronary artery entrance as the seed point on the three-dimensional myocardial image, extracting the coronary artery through regional growth, calculating the average grayscale and average variance of the coronary artery, and extracting the coronary artery along the extending direction of the coronary artery according to the grayscale distribution of the coronary artery Three-dimensional image of coronary artery tree.

Optionally, the above method for accurately acquiring blood flow of a large artery on the heart surface based on CT images, the method for extracting a large artery image based on the three-dimensional image of the heart includes:

Extract the cross section of the aorta and the centerline according to the three-dimensional image of the heart;

Obtain the cross-sectional radius r of the aorta and the total length L of the centerline;

Divide the center line into independent single blood vessels according to the rule of the left binary tree;

Sort the single blood vessels according to the order of the left binary tree to obtain the blood vessel list;

Acquire the aorta image according to the blood vessel list.

Optionally, the above method for accurately obtaining the blood flow of a large artery on the heart surface based on CT images. The method for obtaining the sum V ₁ of the volume of any large artery blood vessel on the surface of the heart and its downstream blood vessels includes:

Obtaining the cross-sectional area S according to the cross-sectional radius r of the aorta;

Obtaining the length L ₁ of the centerline segment between adjacent sections of the aorta according to the collected time difference between the sections of the aorta;

Obtaining the volume V _{11 of} a unit of aortic blood vessel according to the product of each of the cross-sectional areas S and L ₁ ;

According to the cumulative sum of the volume V ₁₁ , the volume sum V _{1 of} any aortic blood vessel on the surface of the heart and its downstream blood vessels is obtained.

Optionally, the above method for accurately acquiring the blood flow of a large artery on the heart surface based on the CT image, and the method for acquiring the volume sum V _t of all blood vessels on the heart surface according to the three-dimensional image of the coronary artery tree includes:

The three-dimensional image of the coronary artery tree contains three aortic vessels;

The cumulative sum of the three aortic vessels V _{1 is} the sum of the volume of all the vessels on the heart surface V _t .

Optionally, in the above method for accurately acquiring the blood flow of a large artery on the cardiac surface based on the CT image, the second blood flow Q is sequentially subjected to Fourier transform and inverse Fourier transform to obtain the corrected first Three blood flow Q _f methods include:

By Fourier transform, the second blood flow Q waveform in the time domain is converted into the third blood flow Q _f waveform in the frequency domain.

In a second aspect, the present application provides a method for obtaining coronary vascular assessment parameters, including:

The above method for accurately obtaining the blood flow of a large artery on the heart surface based on CT images;

Obtain the vascular parameters of the largest congestion state of a large artery mentioned on the heart table;

Based on the corrected third blood flow Q _f waveform and the blood vessel parameters, the coronary blood vessel assessment parameters are obtained.

Alternatively, coronary artery evaluation parameter acquisition methods described above, the blood vessel parameters include: Vascular average diameter D, the total length of the center line L, the average flow velocity v, the inlet pressure P _a coronary artery waveform, distal coronary artery stenosis ΔP waveform of pressure drop at the end.

Optionally, in the above method for obtaining coronary artery blood vessel assessment parameters, the method for obtaining the average blood flow velocity v includes:

According to the cumulative sum of the cross-sectional radius r of the aorta divided by the cumulative number, the average radius r of the blood vessel is obtained;

Obtain the average blood vessel diameter D according to the average blood vessel radius r;

According to the third blood flow Q _f waveform, obtain the average value of Q _f within a heartbeat cycle

Obtain the average blood flow velocity v according to Q _f and D. The specific formula is:

According to the above method for obtaining coronary artery blood vessel assessment parameters, the coronary artery blood vessel assessment parameters include: microcirculation resistance index IMR and coronary blood flow reserve fraction FFR;

Said

Or said

among them,

It represents the average value of the difference between the corresponding points of the P _a waveform and the ΔP pressure waveform in a heartbeat cycle.

Represent the mean coronary inlet pressure P _a P _a waveform of a heartbeat period.

Alternatively, coronary artery evaluation parameter acquisition methods described above, the coronary artery inlet P _a waveform acquisition method comprising:

The diastolic and systolic blood pressure of the patient can be measured according to the non-invasive detector;

According to the formula

Obtain the average arterial pressure, where Psys represents systolic pressure and Pdia represents diastolic pressure;

Based on the CT image, the time t ₁ of the heartbeat cycle of the CT image is obtained;

Adjust the heartbeat cycle time on the known flow velocity waveform to t ₁ ;

Based on the known aortic pressure waveform, the P _z -it ₁ flow waveform is obtained, where i represents the number of heartbeat cycles contained in the P _z -it ₁ flow waveform, i≥1;

According to the formula:

Wherein, P _zt P _z denotes an average value acquired in the flow waveform P _z -it ₁ in the j-th heartbeat period, 1≤j≤i;

According to the formula _{P a = Pz × P t mean} / P zt, acquiring the inlet pressure P _a coronary artery waveform.

Optionally, in the above method for obtaining assessment parameters of coronary arteries, the acquisition method of the pressure drop ΔP waveform at the distal end of the coronary artery stenosis includes:

3D mesh segmentation of 3D image of coronary artery tree;

In each time domain, based on the third blood flow wave Q _f waveform in the time domain, the blood flow velocity waveform in the time domain is obtained based on the blood flow divided by the area equal to the flow rate, and the frequency domain is obtained according to the Fourier transform Blood flow velocity waveform, using numerical method to solve continuity and Navier-Stokes equation to solve the pressure drop ΔP _f from the entrance of coronary artery to the distal end of coronary artery stenosis in frequency domain;

Based on the inverse Fourier transform, the ΔP waveform in the time domain state is obtained.

Optionally, in the above method for obtaining the evaluation parameters of the coronary arteries, the method for solving the continuity and Navier-Stokes equations using the numerical method to obtain the pressure drop ΔP from the entrance of the coronary artery to the distal end of the coronary artery stenosis includes:

The numerical method is used to solve the continuity and Navier-Stokes equations, the specific formula is:

among them,

P, ρ, and μ represent the coronary blood flow velocity, pressure, blood flow density, and blood flow viscosity, respectively.

In a third aspect, the present application provides a device for accurately acquiring blood flow of a large artery on the cardiac surface based on CT images. The method for accurately acquiring blood flow of a large artery on the cardiac surface based on CT images is characterized in that: Including: a first blood flow acquisition unit, a second blood flow acquisition unit and a third blood flow acquisition unit connected in sequence;

The first blood flow obtaining unit is configured to obtain the first blood flow Q _t waveform at the entrance of the coronary artery in the maximum congestion state according to the myocardial volume and a known flow velocity waveform;

The second blood flow acquisition unit is configured to receive the first blood flow Q _t waveform at the entrance of the coronary artery in the maximum congestion state sent by the first blood flow acquisition unit, and acquire any one of the heart surface according to the Q _t waveform The second blood flow Q waveform of the aortic vessel and its downstream vessels;

The third blood flow acquisition unit is configured to receive the second blood flow Q waveform of any aortic vessel on the heart surface and the downstream blood vessel sent by the second blood flow acquisition unit, and sequentially perform the second blood flow Q waveform Fourier transform and inverse Fourier transform to obtain the corrected third blood flow Q _f waveform.

Optionally, the above-mentioned device for accurately acquiring the blood flow of a large artery on the cardiac surface based on the CT image further includes: a three-dimensional myocardial reconstruction unit connected to the first blood flow acquisition unit;

The myocardial three-dimensional reconstruction unit includes a CT image segmentation module, a three-dimensional reconstruction module and a myocardial three-dimensional image module connected in sequence, and the myocardial three-dimensional image module is connected to the first blood flow acquisition unit;

The CT image segmentation module is used to segment the CT image of the heart to obtain CT image information of the computed tomography angiography of the heart;

The three-dimensional reconstruction module is used to receive contrast CT image information sent by the CT image segmentation module, and reconstruct to obtain a three-dimensional image of the heart;

The myocardial three-dimensional image module is configured to receive the three-dimensional image of the heart sent by the three-dimensional reconstruction module, and separate the three-dimensional image of the myocardium from the three-dimensional image of the heart.

According to a fourth aspect, the present application provides a coronary artery analysis system, including: the device for accurately acquiring blood flow of a large artery on the cardiac surface based on any one of the CT images described above.

According to a fifth aspect, the present application provides a computer storage medium. When the computer program is executed by the processor, the above method for accurately acquiring the blood flow of a large artery on the cardiac surface based on the CT image is realized.

The beneficial effects brought by the solutions provided in the embodiments of the present application include at least:

This application provides a method for accurately obtaining blood flow of a large artery on the heart surface based on CT images. Non-invasive detection methods are used. Because non-invasive methods cannot obtain the flow waveform and pressure waveform of patients corresponding to CT images, that is, invasive surgery The real-time flow rate or pressure value in the test results in the problem of inaccurate testing. This application obtains the first blood flow rate Q _t at the entrance of the coronary artery under the maximum congestion state through the previously acquired flow rate waveform of a certain patient. Waveform, and acquiring the second blood flow Q waveform of any aortic vessel on the surface of the heart and its downstream vessels. Further, in this application, the second blood flow Q is first subjected to Fourier transform, and then inverse Fourier transform, Converting the flow wave in the frequency domain back to the flow wave in the time domain to obtain the corrected third blood flow Q _f waveform; calculating the coronary artery vascular assessment parameters by Q _f improves the accuracy of the measurement of the coronary artery vascular assessment parameters.

BRIEF DESCRIPTION

The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation on the present invention. In the drawings:

FIG. 1 is a flowchart of Embodiment 1 of a method for accurately acquiring blood flow of a large artery on a cardiac surface based on CT images of the present application;

Figure 2 is the known flow velocity waveform of this application;

3 is a flowchart of Embodiment 2 of a method for accurately acquiring blood flow of a large artery on a cardiac surface based on CT images of the present application;

4 is a flowchart of step S100 of the present application;

5 is a schematic diagram of myocardial segmentation results of cardiac CT images of the present application;

6 is a flowchart of step S200 of the present application;

7 is a flowchart of step S300 of the present application;

8 is a flowchart of step S310 of the present application;

9 is a schematic diagram of the segmentation result of a large artery with a coronary artery entrance of this application;

10 is a schematic diagram of the segmentation result of the coronary artery entrance of this application;

11 is a schematic diagram of the coronary artery segmentation result of this application;

12 is a schematic diagram of a mesh model of the coronary artery segmentation result of this application;

13 is a flowchart of step S311 of this application;

14 is a schematic diagram corresponding to the blood vessel list and form of the application;

15 is a flowchart of step S320 of the present application;

16 is a flowchart of step S330 of the present application;

17 is a schematic structural diagram of the first blood flow and the second blood flow of the heart and coronary arteries of the present application;

18 is a flowchart of Embodiment 3 of a method for obtaining coronary artery blood vessel evaluation parameters according to this application;

Figure 19 is the known aortic pressure waveform;

20 is a structural block diagram of Embodiment 4 of an apparatus for accurately acquiring blood flow of a large artery on a cardiac surface based on CT images of the present application;

21 is a structural block diagram of another embodiment of an apparatus for accurately acquiring blood flow of a large artery on the cardiac surface based on CT images of the present application;

22 is a structural block diagram of another embodiment of an apparatus for accurately acquiring blood flow of a large artery on the cardiac surface based on CT images of this application;

23 is a structural block diagram of the coronary artery analysis system of the present application;

The reference symbols are explained below:

Myocardial 3D reconstruction unit 100, CT image segmentation module 110, 3D reconstruction module 120, myocardium 3D image module 130, first blood flow acquisition unit 200, myocardial volume module 210, first blood flow Qt module 220, second blood flow acquisition Unit 300, a three-dimensional image module 310 of the coronary artery tree, a single aortic vessel volume module 320, a heart vessel volume module 330, a second blood flow acquisition module 340, a third blood flow acquisition unit 400, and a first flow wave module 410 , Fourier transform module 420, second flow wave module 430, inverse Fourier transform module 440, third flow acquisition module 450, vascular coronary artery blood vessel assessment parameter device 500, average blood flow velocity v module 510, pressure difference module 520, mean coronary inlet pressure module 530, microcirculation resistance index IMR module 540, coronary blood flow reserve fraction FFR module 550.

detailed description

To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be described clearly and completely in conjunction with specific embodiments of the present invention and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

In the following, a plurality of embodiments of the present invention will be disclosed in the form of diagrams. For the sake of clarity, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present invention. That is to say, in some embodiments of the present invention, these practical details are unnecessary. In addition, in order to simplify the drawings, some conventional structures and components will be shown in a simple schematic manner in the drawings.

The vascular assessment parameters include: FFR, IMR, etc .; FFR and IMR need to be based on the average blood flow velocity of the coronary artery, and the average blood flow velocity is related to the blood flow of a large artery on the heart surface of the coronary artery, so any of the heart surface The measurement accuracy of the blood flow of the root aorta directly affects the measurement accuracy of the blood vessel evaluation parameters, and the blood flow measured by the method of the prior art has the problem of inaccuracy.

In order to solve the above problems, a method, device, system and storage medium for obtaining blood flow of the aorta and the aorta.

Example 1:

As shown in FIG. 1, this application provides a method for accurately acquiring blood flow of a large artery on the cardiac surface based on CT images, including:

S200, according to the volume of myocardium and a known flow velocity waveform as shown in FIG. 2 (in the maximum congestion state, the left anterior descending branch, right coronary artery, and left circumflex branch of any patient measured by Doppler ultrasound guide wire Within the waveform), obtain the first blood flow Q _t waveform at the entrance of the coronary artery in the maximum congestion state;

S300, according to the first blood flow Q _t waveform, obtain a second blood flow Q waveform of any aortic blood vessel on the surface of the heart and its downstream blood vessels;

S400: Perform a Fourier transform and an inverse Fourier transform on the second blood flow Q waveform in sequence to obtain a corrected third blood flow Q _f waveform.

This application provides a method for accurately obtaining blood flow of a large artery on the heart surface based on CT images. Non-invasive detection methods are used. Because non-invasive methods cannot obtain the flow waveform and pressure waveform of patients corresponding to CT images, that is, invasive surgery cannot be obtained. The real-time flow rate or pressure value in the test results in the problem of inaccurate testing. This application obtains the first blood flow rate Q _t at the entrance of the coronary artery under the maximum congestion state through the previously acquired flow rate waveform of a certain patient. Waveform, and acquiring the second blood flow Q waveform of any aortic vessel on the surface of the heart and its downstream vessels. Further, in this application, the second blood flow Q is first subjected to Fourier transform, and then inverse Fourier transform, Converting the flow wave in the frequency domain back to the flow wave in the time domain to obtain the corrected third blood flow Q _f waveform; calculating the coronary artery vascular assessment parameters by Q _f improves the accuracy of the measurement of the coronary artery vascular assessment parameters.

Example 2:

As shown in FIG. 3, the present application provides a method for accurately acquiring blood flow of a large artery on the cardiac surface based on CT images, including:

S100, three-dimensional reconstruction of the myocardium is performed according to the CT image of the heart, as shown in FIG. 4:

S110: Segment the CT image of the heart to obtain CT image information of the computed tomography angiography of the heart;

S120, reconstruct and obtain a three-dimensional image of the heart;

S130. Separately obtain the three-dimensional image of the myocardium as shown in FIG. 5 from the three-dimensional image of the heart.

S200, according to the volume of the myocardium, coronary blood flow obtaining a first maximum at the entrance of the congestion state Q _t;

In an embodiment of the present application, as shown in FIG. 6, S200 includes:

S210: Determine the myocardial volume V _r according to the three-dimensional image of the myocardium in S130;

S220, according to the myocardial volume V _r , obtain the first blood flow Q _t at the entrance of the coronary artery under the maximum congestion state, formula (1) is:

Q _t = V _r Q ₀ × K;

Among them, V _r represents myocardial volume; Q ₀ represents myocardial blood flow at rest, Q _{0 is} obtained by cardiac MRI or CT perfusion, or Q ₀ = 2 ～ 2.8ml / min / g; K represents a constant, preferably , K is any positive number from 1 to 3;

Based on the Q _{t mean} and the CT image, the time t ₁ of the heartbeat cycle of the CT image is obtained;

Adjust the heartbeat cycle time on the known flow velocity waveform to t ₁ ;

According to the flow velocity multiplied by the cross-sectional area equal to the blood flow Q _a , obtain the Q _a -it ₁ flow waveform, where i represents the number of heartbeat cycles contained in the Q _a -it ₁ flow waveform, i≥1;

According to the formula:

Among them, Q _at means to obtain the average value of Q _a in j heartbeat cycles in the flow waveform of Q _a -it ₁ , 1≤j≤i;

According to the formula Q _t = Q _a × Q _{t mean} / Q _at , the first blood flow Q _t waveform is obtained.

S300, according to the first blood flow Q _t, acquiring a surface of any large arteries of the heart and vessels downstream of the second blood flow Q;

As shown in FIG. 7, in one embodiment of the present application, S300 includes:

S310: Separately obtain a three-dimensional image of the coronary artery tree from the three-dimensional image of the myocardium;

As shown in FIG. 8, in one embodiment of the present application, S310 includes:

S311, extract the aortic image according to the three-dimensional image of the heart obtained in S120, process the aortic image to obtain a complete aortic complementary image, and perform regional growth to obtain an aortic image including a coronary artery entrance as shown in FIG. 9;

As shown in FIG. 13, in one embodiment of the present application, the method for extracting the aorta image according to the three-dimensional image of the heart obtained in S120 in S311 includes:

S3110, according to the three-dimensional image of the heart, extract the cross section of the aorta and the center line;

S3120, obtaining the cross-sectional radius r of the aorta in S3110 and the total length L of the center line;

S3130, dividing the center line obtained by S3120 into independent single blood vessels according to the rule of the left binary tree;

S3140, sort the single blood vessels in S3130 in the order of the left binary tree to obtain the blood vessel list shown in FIG. 14;

S3150. Render according to the blood vessel list in S3140 to obtain the aorta image.

S312, according to the complementary image of the aorta containing the coronary artery entrance and the whole aorta in S311, an image containing the coronary artery port is obtained, and the coronary artery entrance as shown in FIG. 9 is determined;

S313, taking the coronary artery entrance as the seed point on the three-dimensional myocardial image, extracting the coronary artery through regional growth, calculating the average grayscale and average variance of the coronary artery, and extracting along the extending direction of the coronary artery according to the grayscale distribution of the coronary artery as shown in the figure The three-dimensional image of the arterial tree shown in 11;

S320, according to the three-dimensional image of the coronary artery tree, the volume sum V _{1 of} any aortic blood vessel on the surface of the heart and its downstream blood vessels is obtained;

As shown in FIG. 15, in one embodiment of the present application, S320 includes:

S321, obtaining the cross-sectional area S according to the cross-sectional radius r of the aorta;

S322. Obtain a centerline segment length L ₁ between adjacent aortic cross-sections according to the collected time difference between the cross-sections of each aorta;

S323, obtaining the volume V _{11 of} one unit of the aortic blood vessel according to the product of each cross-sectional area S and L ₁ ;

S324, based on the cumulative sum of the volumes V ₁₁ acquires an arbitrary surface of the heart and large arteries and the downstream vessel volume V _1.

S330, according to the three-dimensional image of the coronary artery tree, obtain the volume sum V _{t of} all blood vessels on the surface of the heart;

As shown in FIG. 16, in one embodiment of the present application, S330 includes:

S331, the three-dimensional image of the coronary artery tree contains three aortic vessels;

S332, obtained according to ₁ V S322, calculates three large arteries V ₁ of the cumulative sum of all vessels of the surface of the heart is the sum of the volumes V _t.

S340. Obtain the second blood flow Q as shown in FIG. 17 according to Q _t , V ₁ , and V _t . The specific formula (2) is:

Q = Q _t × (V ₁ / V _t ) ^3/4 .

In S400, the second blood flow Q is sequentially subjected to Fourier transform and inverse Fourier transform to obtain a corrected third blood flow Q _f .

In an embodiment of the present application, S400 includes: transforming the second blood flow Q waveform in the time domain to a third blood flow Q _f waveform in the frequency domain by Fourier transform.

It is generally assumed that the blood vessel is lossless and the terminal reflection coefficient is 0, but in fact there is a reflected wave, and the reflected wave will be attenuated in propagation. The curve of the second blood flow Q and time t is the flow wave in the time domain after the Fourier transform is Q (w), because the ratio of the pressure wave P (w) and the flow wave Q (w) is the input impedance Z (w), where w is the Fourier transform angular frequency; as the frequency w increases, the reflected wave attenuation will increase, so the influence of the reflected wave will decrease as the reflected wave attenuation increases; When the wave effect is small, the input impedance approaches the characteristic impedance Zc, which is a value independent of the frequency w. After a large number of creative animal experiments, the obtained curve shows that the corresponding input impedance Z (w) at 6 times frequency multiplication is relatively close to the characteristic impedance Zc; therefore, through experiments, the first 1 to 5 arbitrary The second blood flow Q corresponding to the numerical frequency doubling is preferably removed by 1 to 5 times the second blood flow Q corresponding to all the numerical doubling to obtain the filtered second blood flow Q, and then inverse Fourier transform is performed to convert The flow wave in the frequency domain is converted back to the flow wave in the time domain to obtain the corrected third blood flow Q _f , and the coronary vascular assessment parameters are calculated by Q _f , which improves the accuracy of the measurement of the coronary vascular assessment parameters.

Example 3:

As shown in FIG. 18, this application provides a method for obtaining coronary artery vascular assessment parameters, including:

The above method for accurately obtaining the blood flow of a large artery on the heart surface based on CT images;

S500: Obtain the vascular parameters of the largest congestion state of a large artery mentioned on the cardiogram;

S600: Obtain coronary artery blood vessel assessment parameters based on the corrected third blood flow Q _f waveform and the blood vessel parameters.

One embodiment of the present disclosure, the blood vessel parameters include: Vascular average diameter D, the total length of the center line L, the average flow velocity v, the inlet pressure P _a coronary artery waveform, coronary stenosis distal pressure drop ΔP waveform.

In an embodiment of the present application, the method for obtaining the average blood flow velocity v includes:

I, according to the cumulative sum of the cross-sectional radius r of the aorta divided by the cumulative number to obtain the average blood vessel radius r;

II, obtain the average diameter D of the blood vessel according to the average radius r of the blood vessel;

III, according to the third blood flow Q _f waveform, obtain the average value of Q _{f in} a heartbeat cycle

IV. Obtain the average blood flow velocity v according to Q _f and D. The specific formula is:

In an embodiment of the present application, the coronary artery blood vessel assessment parameters include: microcirculation resistance index IMR and coronary blood flow reserve fraction FFR;

Said

Or said

among them,

It represents the average value of the difference between the corresponding points of the P _a waveform and the ΔP pressure waveform in a heartbeat cycle.

Represent the mean coronary inlet pressure P _a P _a waveform of a heartbeat period.

A method of obtaining the waveform of the example embodiment of the present application, the inlet P _a coronary artery comprising:

A) The diastolic blood pressure and systolic blood pressure of the patient are measured according to the non-invasive detector;

B) According to the formula

Obtain the average arterial pressure, where Psys represents systolic pressure and Pdia represents diastolic pressure;

C) Based on the CT image, the time t _{1 of} obtaining the heartbeat cycle of the CT image;

D) Adjust the heartbeat cycle time on the known flow rate waveform to t ₁ ;

E) As shown in FIG. 19, based on the known aortic pressure waveform, the P _z -it ₁ flow waveform is obtained, where i represents the number of heartbeat cycles contained in the P _z -it ₁ flow waveform, i ≥ ₁ ;

F) According to the formula:

Wherein, P _zt P _z denotes an average value acquired in the flow waveform P _z -it ₁ in the j-th heartbeat period, 1≤j≤i;

G) according to the formula _{P a = Pz × P t mean} / P zt, acquiring the inlet pressure P _a coronary artery waveform.

In an embodiment of the present application, the method for acquiring the pressure drop ΔP waveform at the distal end of the coronary artery stenosis includes:

a) Three-dimensional grid segmentation of the three-dimensional image of the coronary artery tree;

b) In each time domain, based on the third blood flow wave Q _f waveform in the time domain, the blood flow velocity waveform in the time domain is obtained based on the blood flow divided by the area equal to the flow rate, and the frequency domain is obtained according to the Fourier transform The blood flow velocity waveform at the lower end, using the numerical method to solve the continuity and Navier-Stokes equation to solve the pressure drop ΔP _f from the entrance of the coronary artery to the distal end of the coronary artery stenosis in the frequency domain;

c) Based on the inverse Fourier transform, find the ΔP waveform in the time domain state.

In an embodiment of the present application, the method of solving the continuity and Navier-Stokes equation using the numerical method to solve the pressure drop ΔP from the entrance of the coronary artery to the distal end of the coronary artery stenosis includes

The numerical method is used to solve the continuity and Navier-Stokes equations, the specific formula is:

among them,

P, ρ, and μ represent the coronary blood flow velocity, pressure, blood flow density, and blood flow viscosity, respectively.

As shown in FIG. 12, the blood vessels are reordered according to the pressure drop ΔP.

Example 4:

As shown in FIG. 20, the present application provides a device for accurately acquiring blood flow of a large artery on the cardiac surface based on CT images. The above method for accurately acquiring blood flow of a large artery on the cardiac surface based on CT images includes: The first blood flow acquisition unit 200, the second blood flow acquisition unit 300, and the third blood flow acquisition unit 400 are connected in sequence; the first blood flow acquisition unit 200 is used to acquire the maximum value based on the myocardial volume and a known flow velocity waveform The first blood flow Q _t waveform at the entrance of the coronary artery in the hyperemic state; the second blood flow acquisition unit 300 is configured to receive the first blood at the entrance of the coronary artery in the maximum congestion state sent by the first blood flow acquisition unit 200 Flow Q _t waveform, according to the Q _t waveform, the second blood flow Q waveform of any aortic blood vessel on the surface of the heart and its downstream blood vessels is obtained; the third blood flow acquisition unit 400 is used to receive the heart sent by the second blood flow acquisition unit 300 The second blood flow Q waveform of any aortic vessel on the surface and its downstream vessels, the Fourier transform and the inverse Fourier transform of the second blood flow Q waveform in turn are obtained after correction The third waveform blood flow Q _f.

As shown in FIG. 21, in an embodiment of the present application, the device for accurately acquiring blood flow of a large artery on the cardiac surface based on CT images further includes: a three-dimensional myocardial reconstruction unit 100 connected to the first blood flow acquiring unit 200; as shown in FIG. As shown in FIG. 22, the myocardial 3D reconstruction unit 100 includes a CT image segmentation module 110, a 3D reconstruction module 120, and a myocardial 3D image module 130 connected in sequence. The myocardial 3D image module 130 is connected to the first blood flow acquisition unit 200; the CT image segmentation module 110 , Used to segment the CT image of the heart to obtain CT image information of the computed tomography angiography of the heart; the 3D reconstruction module 120 is used to receive the CT image information sent by the CT image segmentation module 110 to reconstruct and obtain the 3D image of the heart; the 3D image of the myocardium The module 130 is configured to receive the three-dimensional image of the heart sent by the three-dimensional reconstruction module 120, and separate the three-dimensional image of the myocardium from the three-dimensional image of the heart.

22, one embodiment of the present application, the first blood flow rate acquiring unit 200 comprises: sequentially myocardial volume module 210 and connected to a first blood flow rate Q _t acquisition module 220; cardiac volume and Myocardial dimensional image module 210 module 130 is connected, the first blood flow Q _t module 220 is connected to the second blood flow acquisition unit 300; the myocardial volume module 210 is used to receive the three-dimensional image of the myocardium sent by the three-dimensional myocardial image module 130, and obtain the myocardial volume V _r according to the three-dimensional image of the myocardium ; The first blood flow Q _t module 220 is used to obtain the first blood flow Q _t at the entrance of the coronary artery under the maximum congestion state according to the myocardial volume V _r , the formula (1) is: Q _t = V _r Q ₀ × K; Among them, V _r represents myocardial volume; Q ₀ represents myocardial blood flow at rest, Q _{0 is} obtained by cardiac MRI or CT perfusion, or Q ₀ = 2 ～ 2.8ml / min / g; K represents a constant, preferably , K is any positive number from 1 to 3.

As shown in FIG. 22, in one embodiment of the present application, the second blood flow acquisition unit 300 further includes: a three-dimensional image module 310 of a coronary artery tree connected in sequence, a single aortic vessel volume module 320, and a total vessel volume module on the heart surface 330 and a second blood flow acquisition module 340; the three-dimensional image module 310 of the coronary artery tree is connected to the myocardial three-dimensional image module 130, the second blood flow acquisition module 340 is connected to the single aortic vessel volume module 320, and the third blood flow acquisition unit 400 ; Coronary artery tree three-dimensional module 310, used to receive the three-dimensional image of the myocardium sent by the myocardial three-dimensional image module 130, separated from the three-dimensional image of the myocardium to obtain the three-dimensional image of the coronary artery tree; single aortic vessel volume module 320, used to receive the The three-dimensional image of the coronary artery tree of the arterial tree three-dimensional module 310 obtains the volume sum V _{1 of} any aortic vessel and its downstream vessels on the heart surface; the total vessel volume module 330 on the heart surface is used to receive all single aortic vessel volume modules 320 transmitted V _1, V ₁ according to the cumulative sum of all vessels of the surface of the heart acquired And volume V _t; a second blood flow obtaining module 340 is configured to receive a first blood flow rate Q _t Q _t sent by the module 220, V the volume of the large arteries transmission module _3201, the entire surface of the heart vascular volume module 330 transmits the single For the volume V _t , the second blood flow Q is obtained according to Q _t , V ₁ , and V _t . The specific formula (2) is: Q = Q _t × (V ₁ / V _t ) ^3/4 .

As shown in FIG. 22, in an embodiment of the present application, the third blood flow acquisition unit 400 further includes: a first flow wave module 410, a Fourier transform module 420, a second flow wave module 430, and Fourier connected in sequence The inverse leaf transformation module 440 and the third flow acquisition module 450; the first flow wave module 410 is connected to the second blood flow acquisition module 340; the first flow wave module 410 is used to receive the second sent by the second blood flow acquisition module 340 Blood flow Q, which matches the second blood flow Q with real-time time to generate a curve of the second blood flow Q and time t, which is the flow wave in the time domain; the Fourier transform module 420 is used to receive the first flow wave The flow wave in the time domain sent by the module 410 is converted into the flow wave in the frequency domain by Fourier transform; the second flow wave module 430 is used to receive the Fourier transform module 420 to send The flow wave in the frequency domain of the frequency, the flow wave in the frequency domain is written as the sum of the fundamental frequency and each flow harmonic corresponding to each frequency doubling, remove the corresponding flow harmonics under n frequency doubling, and obtain the filtered frequency Flow wave in the domain; inverse Fourier transform Module 440, configured to receive the filtered frequency-domain down-flow wave sent by the second flow-wave module 430, and convert the flow wave in the frequency domain into a flow wave in the time domain through inverse Fourier transform; the third flow acquisition The module 450 is configured to receive the flow wave in the time domain sent by the inverse Fourier transform module 440, that is, the corrected third blood flow Q _f can be obtained.

Example 5:

The present application provides a coronary artery analysis system, including: any one of the above-mentioned devices for accurately acquiring blood flow of a large artery on the heart surface based on CT images.

As shown in FIG. 23, in one embodiment of the present application, the coronary artery analysis system further includes: a vascular coronary artery vascular assessment parameter device 500 connected to a device for accurately acquiring blood flow of a large artery on the heart surface, vascular coronary artery vascular assessment 500 parameters of the device for acquiring a blood vessel parameters epicardial aortic root of a state of relaxation, comprising: an average vessel diameter D, the total length of the center line L, the average flow velocity v, the mean coronary inlet pressure P _a, coronary stenosis The distal pressure P _d and the coronary blood vessel evaluation parameters are obtained based on the corrected third blood flow Q _f and the blood vessel parameters.

As shown in FIG. 23, in an embodiment of the present application, the vascular coronary artery blood vessel assessment parameter device 500 further includes: an average blood flow velocity v module 510, a pressure difference module 520, an coronary mean pressure module 530, and

A microcirculation resistance index IMR module 540 connected to the average blood flow velocity v module 510, and / or

The coronary blood flow reserve fraction FFR module 550 connected to the average blood flow velocity v module 510;

The average blood flow velocity v module 510 is used to obtain the average blood vessel radius r according to the cumulative sum of the cross-sectional radius r of the aorta divided by the cumulative number; obtain the average blood vessel diameter D according to the average blood vessel radius r obtained in step a; according to Q _f and D obtain the average blood flow velocity v. The specific formula (3) is: v = Q _f / D, where Q _f represents the corrected third blood flow of a large artery on the cardiac surface in S400;

The pressure difference module 520 is used to binarize the three-dimensional image of the coronary artery and draw an isosurface image to obtain the three-dimensional grid image of the coronary artery as shown in FIG. 12; the numerical method is used to solve the continuity and Navier-Stokes equations Solve the pressure drop △ P from the entrance of the coronary artery to the distal end of the coronary artery stenosis, specifically: according to the formula

among them,

P, ρ, μ represent the instantaneous blood flow velocity, pressure, blood flow density, blood flow viscosity of the coronary artery; the inlet boundary conditions are: the maximum congestion state, the inlet flow velocity of the coronary artery stenosis v ₁ , v ₂ , V ₃ , v ₄ , v ₅ , where v ₁ , v ₂ , v ₃ , v ₄ , v ₅ are the blood flow velocities located at 0, 0.2, _0.4 , 0.6, 0.8 radius positions from the center line; The formula ΔP = a [mv + nv ² ] × ∫f ₁ (x) dx + b [mv + nv ² ] × ∫f ₂ (x) dx to obtain the real-time pressure drop ΔP ₁ and ΔP _{2 at the} distal end of coronary artery stenosis , ΔP ₃ …, where a, b, m, and n are constants, and the value is a positive number greater than zero; according to the formula △ P = ∑ △ P _i (i = 1, 2, 3 ...), obtain The pressure drop ΔP from the entrance of the coronary artery to the distal end of the coronary artery stenosis;

Coronary artery inlet mean pressure module 530 is used to measure P _{a1 in} real time according to the non-invasive detector 600; match the real-time measured P _a1 with real-time time to generate a curve of P _a1 and time t, which is the pressure wave in time ; Through Fourier transform, the pressure wave in the time domain is converted into a pressure wave in the frequency domain; the pressure wave in the frequency domain is written as the sum of the pressure harmonics corresponding to the fundamental frequency and each frequency multiplier; remove n Corresponding pressure harmonics at frequency doubling; by inverse Fourier transform, converting pressure waves in the frequency domain into pressure waves in the time domain; obtaining the mean coronary inlet pressure P _a ;

Microcirculation resistance index IMR module 540, the mean blood flow velocity v for receiving module 510 is the average blood flow velocity v transmission, differential pressure receiving module 520 sends the pressure difference between the inlet and the coronary artery mean pressure module 530 transmits the P _a, in accordance with The formula IMR = P _d × T, T = L / v, P _d = P _a- △ P; the average coronary inlet pressure P _a obtained by averaging the inlet pressure P _a1 measured by the noninvasive detector 600 in real time or below The mean coronary pressure P _a obtained by Fourier transform and inverse Fourier transform is substituted into the formula to obtain the IMR value, where T represents the average conduction time in the maximum congestion state.

Fractional FFR coronary flow reserve module 550, a pressure difference between a pressure receiving module 520 sends the difference, and coronary artery mean pressure inlet module 530 transmits the P _a, according to the FFR = P _d / P _a; the real-time non-invasive measurement detector The obtained inlet pressure P _a1 or the average coronary inlet pressure P _a obtained by Fourier transform and inverse Fourier transform below is substituted into the formula to obtain the FFR value.

Example 6:

The present application provides a computer storage medium. When the computer program is executed by the processor, the above method for accurately acquiring the blood flow of a large artery on the cardiac surface based on the CT image is realized.

Those skilled in the art know that various aspects of the present invention can be implemented as a system, method, or computer program product. Therefore, various aspects of the present invention may be specifically implemented in the form of: a complete hardware implementation, a complete software implementation (including firmware, resident software, microcode, etc.), or a combination of hardware and software implementation, It can be collectively referred to as "circuit", "module" or "system" here. In addition, in some embodiments, various aspects of the present invention may also be implemented in the form of a computer program product in one or more computer-readable media that contains computer-readable program code. Implementation of the method and / or system of embodiments of the invention may involve performing, or completing selected tasks manually, automatically, or a combination thereof.

For example, hardware for performing selected tasks according to embodiments of the present invention may be implemented as a chip or a circuit. As software, selected tasks according to embodiments of the present invention may be implemented as multiple software instructions executed by a computer using any suitable operating system. In an exemplary embodiment of the present invention, one or more tasks according to exemplary embodiments of the method and / or system as described herein are performed by a data processor, such as a computing platform for executing multiple instructions. Optionally, the data processor includes a volatile storage for storing instructions and / or data and / or a non-volatile storage for storing instructions and / or data, for example, a magnetic hard disk and / or Removable media. Optionally, a network connection is also provided. Optionally, a display and / or user input device such as a keyboard or mouse are also provided.

Any combination of one or more computer readable may be utilized. The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or device, or any combination of the above. A more specific example of a computer-readable storage medium (non-exhaustive list) will include the following:

Electrical connection with one or more wires, portable computer disk, hard disk, random access memory (RAM), read only memory (ROM), erasable programmable read only memory (EPROM or flash memory), optical fiber, portable compact disk Read only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination of the above. In this document, the computer-readable storage medium may be any tangible medium that contains or stores a program, and the program may be used by or in combination with an instruction execution system, apparatus, or device.

The computer-readable signal medium may include a data signal that is propagated in baseband or as part of a carrier wave, in which computer-readable program code is carried. This propagated data signal can take many forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium, and the computer-readable medium may send, propagate, or transmit a program for use by or in combination with an instruction execution system, apparatus, or device. .

The program code contained on the computer-readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wired, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

For example, any combination of one or more programming languages can be used to write computer program code for performing operations for various aspects of the invention, including object-oriented programming languages such as Java, Smalltalk, C ++, and conventional procedural programming languages, such as "C" programming language or similar programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as an independent software package, partly on the user's computer and partly on a remote computer, or entirely on the remote computer or server. In situations involving remote computers, the remote computer may be connected to the user's computer through any kind of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (for example, through an Internet service provider Internet connection).

It should be understood that each block of the flowchart and / or block diagram and a combination of blocks in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, special-purpose computer, or other programmable data processing device, thereby producing a machine that causes these computer program instructions to be executed by the processor of the computer or other programmable data processing device A device that implements the functions / actions specified in one or more blocks in the flowchart and / or block diagram is generated.

These computer program instructions may also be stored in a computer-readable medium. These instructions cause the computer, other programmable data processing apparatus, or other equipment to work in a specific manner, so that the instructions stored in the computer-readable medium generate Articles of manufacture that implement the instructions of the functions / actions specified in one or more blocks in the flowchart and / or block diagram.

Computer program instructions can also be loaded onto a computer (eg, coronary artery analysis system) or other programmable data processing device to cause a series of operating steps to be performed on the computer, other programmable data processing device, or other device to produce a computer-implemented process So that instructions executed on a computer, other programmable device, or other equipment provide a process for implementing the functions / acts specified in the flowcharts and / or one or more block diagram blocks.

The above specific examples of the present invention further describe the purpose, technical solution and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Within the spirit and principle of the present invention, any modifications, equivalent replacements, improvements, etc., shall be included in the protection scope of the present invention.

Claims (20)

1. The method for accurately acquiring the blood flow of a large artery on the cardiac surface based on CT images is characterized by including:

   According to the myocardial volume and a known flow velocity waveform, obtain the first blood flow Q _t waveform at the entrance of the coronary artery in the maximum congestion state;

   Obtaining the second blood flow Q waveform of any aortic blood vessel on the surface of the heart and the downstream blood vessel according to the first blood flow Q _t waveform;

   Perform a Fourier transform on the second blood flow Q waveform in sequence to obtain a corrected third blood flow Q _f waveform.
2. The method for accurately obtaining the blood flow of a large artery on the cardiac surface based on a CT image according to claim 1, characterized in that, according to the myocardial volume, the first blood flow Q at the entrance of the coronary artery in the state of maximum congestion is obtained The method of _t also includes: three-dimensional reconstruction of myocardium based on cardiac CT images, specifically:

   Segment the CT image of the heart to obtain CT image information of the computed tomography angiography of the heart;

   Reconstruction to obtain a three-dimensional image of the heart;

   Separately obtain a three-dimensional image of the myocardium from the three-dimensional image of the heart.
3. The method for accurately obtaining the blood flow of a large artery on the cardiac surface based on a CT image according to claim 2, wherein the first blood flow at the entrance of the coronary artery is obtained according to the volume of myocardium and a known flow velocity waveform The methods of Q _t include:

   Determine the myocardial volume V _r according to the three-dimensional image of the myocardium;

   According to the volume of myocardium, the average blood flow Q _{t mean} at the entrance of the coronary artery under the maximum congestion state is obtained, the formula is:

   Q _{t mean} = V _r × Q ₀ × K;

   Among them, V _r represents myocardial volume; Q ₀ represents resting myocardial blood flow, Q _{0 is} obtained by cardiac magnetic resonance MRI or CT perfusion, or Q ₀ = 2 ～ 2.8ml / min / _g ; K represents a constant;

   Based on the Q _{t mean} and the CT image, the time t ₁ of the heartbeat cycle of the CT image is obtained;

   Adjust the heartbeat cycle time on the known flow velocity waveform to t ₁ ;

   According to the flow velocity multiplied by the cross-sectional area equal to the blood flow Q _a , obtain the Q _a -it ₁ flow waveform, where i represents the number of heartbeat cycles contained in the Q _a -it ₁ flow waveform, i≥1;

   According to the formula:

   

   Among them, Q _at means to obtain the average value of Q _a in j heartbeat cycles in the flow waveform of Q _a -it ₁ , 1≤j≤i;

   According to the formula Q _t = Q _a × Q _{t mean} / Q _at , the first blood flow Q _t waveform is obtained.
4. The method for accurately obtaining the blood flow of a large artery on the heart surface according to the CT image according to claim 2, wherein the method for obtaining the second blood flow Q of any aortic blood vessel and its downstream blood vessels on the surface of the heart includes :

   Separate the three-dimensional image of the coronary artery tree from the three-dimensional image of the myocardium;

   According to the three-dimensional image of the coronary artery tree, the volume sum V _{1 of} any aortic vessel on the surface of the heart and its downstream vessels is obtained;

   Obtain the sum V _t of the volume of all blood vessels on the heart surface according to the three-dimensional image of the coronary artery tree;

   Obtain the second blood flow Q according to Q _t , V ₁ , and V _t , the specific formula is:

   Q = Q _t × (V ₁ / V _t ) ^3/4 .
5. The method for accurately obtaining the blood flow of a large artery on the cardiac surface based on CT images according to claim 4, wherein the method for separating and obtaining the three-dimensional image of the coronary artery tree from the three-dimensional image of the myocardium includes:

   Extract the aorta image according to the three-dimensional image of the heart, process the aorta image to obtain a complete aorta complementary image, perform regional growth, and obtain an aorta image including a coronary artery entrance;

   Determine the entrance of the coronary artery based on the image of the aorta containing the entrance of the coronary artery and the complementary image of the whole aorta to obtain an image containing the entrance of the coronary artery;

   Taking the coronary artery entrance as the seed point on the three-dimensional myocardial image, extracting the coronary artery through regional growth, calculating the average grayscale and average variance of the coronary artery, and extracting the coronary artery along the extending direction of the coronary artery according to the grayscale distribution of the coronary artery Three-dimensional image of coronary artery tree.
6. The method for accurately acquiring the blood flow of a large artery on the heart surface based on a CT image according to claim 5, wherein the method for extracting a large artery image from the three-dimensional image of the heart includes:

   Extract the cross section of the aorta and the centerline according to the three-dimensional image of the heart;

   Obtain the cross-sectional radius r of the aorta and the total length L of the centerline;

   Divide the center line into independent single blood vessels according to the rule of the left binary tree;

   Sort the single blood vessels according to the order of the left binary tree to obtain the blood vessel list;

   Acquire the aorta image according to the blood vessel list.
7. The method for accurately obtaining the blood flow of a large artery on the heart surface based on CT images according to claim 6, wherein the method for obtaining the sum V ₁ of the volume of any aortic vessel on the surface of the heart and its downstream vessels includes :

   Obtaining the cross-sectional area S according to the cross-sectional radius r of the aorta;

   Obtaining the length L ₁ of the centerline segment between adjacent sections of the aorta according to the collected time difference between the sections of the aorta;

   Obtaining the volume V _{11 of} a unit of aortic blood vessel according to the product of each of the cross-sectional areas S and L ₁ ;

   According to the cumulative sum of the volume V ₁₁ , the volume sum V _{1 of} any aortic blood vessel on the surface of the heart and its downstream blood vessels is obtained.
8. The method for accurately acquiring the blood flow of a large artery on the heart surface based on a CT image according to claim 7, characterized in that, based on the three-dimensional image of the coronary artery tree, a volume sum V _{t of} all blood vessels on the surface of the heart is acquired The methods include:

   The three-dimensional image of the coronary artery tree contains three aortic vessels;

   The cumulative sum of the three aortic vessels V _{1 is} the sum of the volume of all the vessels on the heart surface V _t .
9. The method for accurately acquiring the blood flow of a large artery on the cardiac surface based on a CT image according to any one of claims 1 to 8, wherein the second blood flow Q is sequentially subjected to Fourier transform and Fourier transform The method of inverse Fourier transform to obtain the corrected third blood flow Q _f includes:

   By Fourier transform, the second blood flow Q waveform in the time domain is converted into the third blood flow Q _f waveform in the frequency domain.
10. A method for obtaining assessment parameters of coronary arteries includes:

    The method for accurately obtaining the blood flow of a large artery on the cardiac surface based on CT images according to any one of claims 1 to 9;

    Obtain the vascular parameters of the largest congestion state of a large artery mentioned on the heart table;

    Based on the corrected third blood flow Q _f waveform and the blood vessel parameters, the coronary blood vessel assessment parameters are obtained.
11. The method of obtaining coronary artery evaluation parameter according to claim 10, wherein said blood vessel parameter comprises: Vascular average diameter D, the total length of the center line L, the average flow velocity v, the inlet pressure P _a coronary artery waveform , Pressure drop ΔP waveform at the distal end of coronary artery stenosis
12. The method for obtaining coronary artery vascular assessment parameters according to claim 11, wherein the method for obtaining the average blood flow velocity v includes:

    According to the cumulative sum of the cross-sectional radius r of the aorta divided by the cumulative number, the average radius r of the blood vessel is obtained;

    Obtain the average blood vessel diameter D according to the average blood vessel radius r;

    According to the third blood flow Q _f waveform, obtain the average value of Q _f within a heartbeat cycle

    

    Obtain the average blood flow velocity v according to Q _f and D. The specific formula is:

    
13. The method for obtaining coronary artery vascular assessment parameters according to claim 12, wherein the coronary artery vascular assessment parameters include: microcirculation resistance index IMR and coronary blood flow reserve fraction FFR;

    Said

    

    Or said

    

    among them,

    

    Represents the average value of the difference between the corresponding points of the _Pa waveform and the ΔP pressure waveform within a heartbeat cycle,

    

    Represent the mean coronary inlet pressure P _a P _a waveform of a heartbeat period.
14. The method of obtaining coronary artery evaluation parameter according to claim 11, wherein said coronary artery inlet P _a waveform acquisition method comprising:

    The diastolic and systolic blood pressure of the patient can be measured according to the non-invasive detector;

    According to the formula

    

    Obtain the average arterial pressure, where Psys represents systolic pressure and Pdia represents diastolic pressure;

    Based on the CT image, the time t ₁ of the heartbeat cycle of the CT image is obtained;

    Adjust the heartbeat cycle time on the known flow velocity waveform to t ₁ ;

    Based on the known aortic pressure waveform, the P _z -it ₁ flow waveform is obtained, where i represents the number of heartbeat cycles contained in the P _z -it ₁ flow waveform, i≥1;

    According to the formula:

    

    Wherein, P _zt P _z denotes an average value acquired in the flow waveform P _z -it ₁ in the j-th heartbeat period, 1≤j≤i;

    According to the formula P _a = P _z × P _{t mean} / P _zt , the waveform of the coronary inlet pressure P _{a is obtained} .
15. The method for obtaining assessment parameters of coronary arteries according to claim 14, wherein the acquisition method of the pressure drop ΔP waveform at the distal end of the coronary artery stenosis includes:

    3D mesh segmentation of 3D image of coronary artery tree;

    In each time domain, based on the third blood flow wave Q _f waveform in the time domain, the blood flow velocity waveform in the time domain is obtained based on the blood flow divided by the area equal to the flow rate, and the frequency domain is obtained according to the Fourier transform Blood flow velocity waveform, using numerical method to solve continuity and Navier-Stokes equation to solve the pressure drop ΔP _f from the entrance of coronary artery to the distal end of coronary artery stenosis in frequency domain;

    Based on the inverse Fourier transform, the ΔP waveform in the time domain state is obtained.
16. The method for obtaining assessment parameters of coronary arteries according to claim 15, characterized in that the method for solving the continuity and Navier-Stokes equations to obtain the pressure drop ΔP from the entrance of the coronary artery to the distal end of the coronary artery stenosis using a numerical method include:

    The numerical method is used to solve the continuity and Navier-Stokes equations, the specific formula is:

    

    

    among them,

    

    P, ρ, and μ represent the coronary blood flow velocity, pressure, blood flow density, and blood flow viscosity, respectively.
17. A device for accurately acquiring blood flow of a large artery on the heart surface based on a CT image, for a method for accurately acquiring blood flow of a large artery on the heart surface based on a CT image according to any one of claims 1 to 10, characterized in that Including: a first blood flow acquisition unit, a second blood flow acquisition unit and a third blood flow acquisition unit connected in sequence;

    The first blood flow obtaining unit is configured to obtain the first blood flow Q _t waveform at the entrance of the coronary artery in the maximum congestion state according to the myocardial volume and a known flow velocity waveform;

    The second blood flow acquisition unit is configured to receive the first blood flow Q _t waveform at the entrance of the coronary artery in the maximum congestion state sent by the first blood flow acquisition unit, and acquire any one of the heart surface according to the Q _t waveform The second blood flow Q waveform of the aortic vessel and its downstream vessels;

    The third blood flow acquisition unit is configured to receive the second blood flow Q waveform of any aortic vessel on the heart surface and the downstream blood vessel sent by the second blood flow acquisition unit, and sequentially perform the second blood flow Q waveform Fourier transform and inverse Fourier transform to obtain the corrected third blood flow Q _f waveform.
18. The device for accurately acquiring the blood flow of a large artery on the cardiac surface based on a CT image according to claim 17, further comprising: a three-dimensional myocardial reconstruction unit connected to the first blood flow acquisition unit;

    The myocardial three-dimensional reconstruction unit includes a CT image segmentation module, a three-dimensional reconstruction module and a myocardial three-dimensional image module connected in sequence, and the myocardial three-dimensional image module is connected to the first blood flow acquisition unit;

    The CT image segmentation module is used to segment the CT image of the heart to obtain CT image information of the computed tomography angiography of the heart;

    The three-dimensional reconstruction module is used to receive contrast CT image information sent by the CT image segmentation module, and reconstruct to obtain a three-dimensional image of the heart;

    The myocardial three-dimensional image module is configured to receive the three-dimensional image of the heart sent by the three-dimensional reconstruction module, and separate the three-dimensional image of the myocardium from the three-dimensional image of the heart.
19. A coronary artery analysis system, characterized by comprising: the device for accurately acquiring the blood flow of a large artery on the heart surface based on CT images according to any one of claims 17 to 18.
20. A computer storage medium, characterized in that, when a computer program is executed by a processor, the method for accurately acquiring the blood flow of a large artery on the cardiac surface based on a CT image according to any one of claims 1 to 10 is realized.

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